One Health research conference - 9 December 2025

Alexander Weigand¹

¹National Museum of Natural History Luxembourg, 25 Rue Münster, L-2160 Luxembourg, Luxembourg

Abstract

VectorNet is a joint project of the European Center for Disease Control (ECDC) and the European Food Safety Authority (EFSA), aiming at increasing overall preparedness for vector-borne diseases. The National Museum of Natural History of Luxembourg (MNHNL) acts as the national contact point for VectorNet.

Here, updated information on arthropod vectors of medical and veterinary importance in Luxembourg is presented. More precisely, the diversity and currently known distribution of relevant ticks (Acari, Ixodida), mosquitoes (Diptera, Culicidae) and sand flies (Diptera, Psychodidae, Phlebotominae) will be presented. Also, preliminary data from field surveys conducted during 2025 for Culicoides midges (Diptera, Ceratopogonidae) will be presented. Due to changing environmental conditions and increased globalization, several new arthropod vectors of medical or veterinary importance have been detected, have arrived or have further spread in the country over the last years, notably Hyalomma marginatum, Hyalomma rufipes, Dermacentor reticulatus, Rhipicephalus sanguineus s.l., Aedes albopictus, and Phlebotomus mascittii.

To assess vector-related disease risks, surveillance of main entomological vector species is important to determine presence, spread, abundance, as well as other vectorial capacity traits. Since 2024, the European ‘OneHealth4Surveillance’ network has been established. Within this network, nationally coordinated by LIH and ALVA, surveillance of ticks and tick-borne diseases is assisted by several national institutions (e.g. MNHNL, natur&ëmwelt Centre de Soins) and citizens. Mosquito surveillance (in particular for invasive Aedes spp.) is led by the Direction de la Santé in cooperation with LIST. Additionally, sandflies and Culicoides midges are targeted by the MNHNL. Distribution data for entomological vectors is annually uploaded to the Global Biodiversity Information Facility (GBIF) platform.

Krawczyk A. I^1*, Gamio C. ¹, Reteng P. ¹, Aurélie Sausy¹, Alexander M. Weigand², Lena De Baets³, Guillaume Fournier³, Manon Bourg³, Louis Kox⁴, Jill Gaasch⁴, Caroline Merten³, Hübschen, J. M. ¹

¹Clinical and Applied Virology Group, Department of Infection and Immunity, Luxembourg Institute of Health

²Musée National d’Histoire Naturelle de Luxembourg, Luxembourg, Luxembourg

³Luxembourg Veterinary and Food Administration (ALVA)

⁴Centre de Soins pour la Faune Sauvage, Natur&Emwelt

*Presenting author

Abstract

Tick-borne diseases of humans and animals are on the rise due to the geographical expansion of their tick vectors and higher frequencies of infected ticks. The distribution and density of ticks, as well as the prevalence of tick-borne pathogens, are currently under-characterized in Luxembourg. Therefore, surveillance activities have been implemented in the country in the context of the EU co-funded OneHealth4Surveillance project (2024-2026).

Since April 2024, ticks have been collected monthly via blanket dragging in 41 sites across Luxembourg. These sampling sites are primarily green spaces frequently visited by the public, such as parks, forests, and hiking trails. In addition, ticks collected from living and dead animals are investigated. Tick species are identified morphologically and if required by barcoding. DNA and RNA is extracted from all collected ticks and screened for tick-borne pathogens, including tick-borne encephalitis virus and Borrelia burgdorferi sensu lato.

Tick collection and analyses for tick-borne pathogens are ongoing. Preliminary findings on the spatiotemporal distribution of ticks and the prevalence of selected tick-borne pathogens in Luxembourg will be shared during the conference.

This surveillance will provide critical insights into our understanding of tick-borne disease risk in Luxembourg, particularly in green spaces with high public usage. The data generated will support One Health initiatives and contribute to European efforts to monitor and mitigate the emergence of tick-borne diseases.

Acknowledgements

We wish to thank all the people involved in sample collection and testing. Tick and tick-borne pathogens surveillance activities are supported by co-funding from the European Union’s EU4Health programme under Grant Agreement No. 101132473 OH4Surveillance.

Disclaimer: Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or HaDEA. Neither the European Union nor the granting authority can be held responsible for them.

Manon Chassaing¹, Cécile Walczak¹, Aurélie Sausy², Delphine Collard¹, Gwenaëlle Le Coroller², Manon Bourg³, Judith M. Hübschen², Henry-Michel Cauchie¹, Leslie Ogorzaly¹*^,** and Chantal J. Snoeck²**

¹LIST - Luxembourg Institute of Science and Technology

²LIH – Luxembourg Institute of Health

³ALVA - Luxembourg Veterinary and Food Administration

*Presenting author

**These authors contributed equally to this work and share the last authorship.

Abstract

Although wastewater-based surveillance has proven effective in monitoring viral circulation in humans, this approach is incomplete as many emerging viral threats originate in animal reservoirs. To address this issue, we adopted a One Health approach, using surface water as a surveillance tool to monitor viral circulation among humans, animals and vectors within interconnected ecosystems.

Between August 2022 and August 2024, ten freshwater sites across Luxembourg were sampled bi-monthly. Sites were selected based on proximity to wildlife and livestock faecal contamination sources and potential mosquito breeding areas. Viruses were concentrated by ultrafiltration and detected by RT-qPCR. Noroviruses (NoV GI-III), human/bovine enteroviruses (h/bEntV), influenza A virus (IAV), porcine respiratory coronavirus (PRCV), bovine respiratory syncytial virus (bRSV), bovine coronavirus (bCoV) and Usutu virus (UsuV) were targeted.

Of the 4,790 analyses conducted, 557 (11.6%) returned positive results. Only enteric viruses (NoV and EntV) were detected, with no evidence of IAV, PRCV, bCoV, bRSV or UsuV. In rivers near livestock production areas, NoV GI, GII, GIII, hEntV and bEntV were detected in 70.8%, 41.1%, 45.3%, 5.2% and 84.4% of samples, respectively, with RNA concentrations ranging from 9.10² to 3.10⁶ copies/L. In contrast, the same viruses were mostly detected below quantification limits at sites impacted by wildlife or mosquitoes.

These results highlight that the proximity of livestock had a strong influence on the detection of enteric viruses in surface water. Our innovative study showed that monitoring surface water has the potential to provide valuable complementary surveillance, paving the way for additional technological improvements that will enable comprehensive viral risk assessment at the human-animal-environment interface.

Acknowledgement: This study was supported by the Luxembourg National Research Fund (C21/BM/15793340/VIRALERT).

Chantal J. Snoeck¹*, Aurélie Sausy¹, Lena de Baets², Louis Kox³, Jill Gaasch³, Guillaume Fournier², Manon Bourg², Caroline Merten², Judith M. Hübschen¹

¹Clinical and Applied Virology Group, Department of Infection and Immunity, Luxembourg Institute of Health

²Luxembourg Veterinary and Food Administration (ALVA)

³Centre de Soins pour la Faune Sauvage, Natur&Emwelt

*Presenting author

Abstract

Although the burden of mosquito-borne diseases has traditionally been high in (sub-)tropical regions, it is expected to also increase in Europe in the future. West Nile (WNV) and Usutu (USUV) viruses are already enzootic in certain European regions, with widening geographic repartition. The two viruses share similar epidemiological characteristics such as bird-to-bird transmission through mosquito (mainly Culex pipiens) bites. Both viruses may also be transmitted to mammals, including humans, leading to a wide range of symptoms. Therefore, WNV and USUV surveillance in birds – shown to be cost-effective and timely to provide early warning signal for increased risk of transmission to human - was initiated in Luxembourg in 2018. The first USUV case was detected in 2020 in the capital^[1]. Starting in 2024, the surveillance activities were intensified in the framework of the EU project “OneHealth4Surveillance” by screening systematically a wider range of bird species. While WNV has not yet been detected in Luxembourg, USUV was detected again in several birds during the summer and fall of 2024 and in the summer of 2025. Phylogenetic analyses based on whole genomes suggest that the 2024-2025 strains do not originate from a new virus introduction but that USUV was rather maintained in the region since 2020. This finding, together with the overlapping host and vector range of WNV and USUV, suggests that local conditions would likely also allow the maintenance of WNV in the area once introduced, with wider consequences for public and animal health. 

[1] Snoeck CJ, Sausy A, Losch S, Wildschutz F, Bourg M, Hübschen JM (2022). Usutu Virus Africa 3 Lineage, Luxembourg, 2020. Emerg Infect Dis 28(5):1076-1079

Acknowledgements

We wish to thank all the people involved in animal care, sample collection and testing. Flavivirus surveillance activities are a collaborative effort between LIH, ALVA, Administration de la Nature et des Forêts and the Centre de Soins pour la Faune Sauvage. These activities are supported by co-funding from the European Union’s EU4Health programme under Grant Agreement No. 101132473 OH4Surveillance, the Ministry of Agriculture, Food and Viticulture of Luxembourg and LIH.

Disclaimer: Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or HaDEA. Neither the European Union nor the granting authority can be held responsible for them.

Jakob Zinsstag, Professor, PhD, DVM; Head of Unit Human and Animal Health & Group Leader One Health, Swiss Tropical and Public Health Institute

Abstract tbc

R. Schober¹, Y. Pires-Afonso¹, C. Ernst¹, D. Bejko¹, X. Collette¹, T. Velez¹, E. Culetto¹, I. Kerrec¹, D. Gashi¹, P. Hoffmann¹, G. Urth¹, G. Scheiden¹, J. Mossong¹, A. Vergison^1*

¹Luxembourg Directorate of Health, Health Inspection, Luxembourg

*Presenting author

Abstract

A One Health approach calls for integrated surveillance that unites human, animal, and environmental health, while monitoring drivers of disease emergence such as climate change. Here, we report two recent outbreaks in Luxembourg that coincided with a heat wave, requiring a coordinated One Health approach and response.

The first outbreak, involving Legionnaires’ disease (LD), included ten confirmed cases linked to the commune of Steinfort, seven of whom were clustered in or near a local long-term care facility (LTCF). We investigated various potential sources including the water distribution system, the LTCF, two nearby cooling towers, a lake fountain and a cross-border wastewater treatment plant. Environmental sampling was undertaken in collaboration with LIST, LNS, ITM, AGE, and the Administration for the Environment, with typing support from the EU Reference Laboratory in Lyon.

The second outbreak, caused by Yersinia enterocolitica O:9, consisted of 30 genetically identical cases since May with a clear peak at the end of June 2025. Yersinia enterocolitica is primarily foodborne, with pork, vegetables, or unpasteurized dairy products being responsible. Case investigations suggested a Luxembourg-based food source distributed in canteens.

Investigations for both outbreaks are still ongoing, and we will present latest findings including collaborations with our cross-sectoral One Health partners. Climate change may influence both pathogens in the future, as rising temperatures and humidity could increase LD risk, while altered agricultural practices may affect foodborne pathogen dynamics. These outbreaks show the importance of One Health approach and cross sector collaborations when investigating environmental and food-borne infectious outbreaks.

Acknowledgements:

We would like to acknowledge contribution of our partners, Henry-Michel Cauchie, Leslie Ogorzaly, Delphine Collard, Cecile Walczak, Monique Perrin, Catherine Ragimbeau and Jainaba Roussel.

A.C. Frantz*, M. Heddergott

¹Musée National d’Histoire Naturelle, 25 rue Muenster, L-2160 Luxembourg

*Presenting author

Abstract

The raccoon roundworm (Baylisascaris procyonis), a gastrointestinal nematode of the raccoon (Procyon lotor), excretes eggs in its droppings that, if ingested, can cause severe disease in a range of vertebrates. In humans, this may result in a severe form of larval migrans, potentially leading to death or permanent neurological damage. Although roundworms were inadvertently introduced to Europe alongside their raccoon hosts, the parasite is not present in every raccoon population. It is important to understand the geographic distribution of B. procyonis, as early and rapid treatment can prevent severe pathologies in humans. In Western and Central Europe, raccoons are especially common in Germany. While the raccoon roundworm was known to occur in some German populations, its precise European distribution was unknown. However, both the raccoons and the roundworm are currently increasing their geographic distribution. We investigated the precise distribution of the roundworm in Western and Central Europe, as well as used genetic tools to infer colonisation histories and invasion pathways of both the raccoons and the roundworm. We show that raccoons were introduced multiple times, but that not all founder populations were infested with B. procyonis. We present evidence for the roundworm spreading into naïve raccoons population through natural dispersal of infected raccoons. We also present the first evidence for the presence of B. procyonis in Luxembourg, where up to 50% of adult raccoons are infested with the parasite. Persons likely to come into contact with raccoons, as well as health practitioners, should be made aware of the presence of the parasite.

Patrick Reteng^1*, Morten Rasmussen², Aleksander Ring², Christine Harbusch³, Judith M. Hübschen¹

¹Clinical and Applied Virology Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg

²Virus Research and Development Laboratory, Statens Serum Institut, Copenhagen, Denmark

³ProChirop, Bureau of Bat Research and Conservation

*Presenting author

Abstract

Bats (order Chiroptera) are increasingly being recognized as a reservoir host for several viruses of zoonotic concern, notably those belonging to the families Coronaviridae, Paramyxoviridae, and Astroviridae. Given their geographical distribution and mobility, bats play a significant role in the ecology of emerging infectious diseases. Consequently, they represent a pivotal focal point for virus surveillance under the One Health approach. A previous study from Luxembourg provided initial evidence of circulation of paramyxovirus, alpha-, and betacoronaviruses in local bat populations.^[1] However, the viruses were detected using a targeted approach and therefore, other viruses could have been missed. To expand on the initial findings, a comprehensive approach using metagenomics sequencing is being employed for samples collected from captured individuals across six different sites in Luxembourg. Oropharyngeal swabs are subjected to a next-generation sequencing workflow. To enhance the sensitivity and specificity of virus detection, sequencing libraries are enriched using a commercially available probe-based target capture system designed to detect a broad range of known vertebrate viruses. This study aims to characterize the virome of local bat populations, as well as to assess the utility of metagenomics sequencing in proactive virus surveillance. The results will contribute valuable insights for regional pathogen monitoring efforts and inform future risk assessments regarding emerging bat-related viruses.

Reference:

[1] Pauly M, Pir JB, Loesch C, Sausy A, Snoeck CJ, Hübschen JM, Muller CP. 2017. Novel Alphacoronaviruses and Paramyxoviruses Cocirculate with Type 1 and Severe Acute Respiratory System (SARS)-Related Betacoronaviruses in Synanthropic Bats of Luxembourg. Appl Environ Microbiol 83:e01326-17.

Leslie Ogorzaly¹*, Héléna Wolf¹, Cécile Walczak¹, Malte Herold¹, Henry-Michel Cauchie¹

¹LIST - Luxembourg Institute of Science and Technology

*Presenting author

Growing interest in wastewater reuse raises concerns about plant pathogens in reclaimed water that can infect crops, causing yield losses and economic damage.

Firstly, we analysed twelve raw wastewater and ten surface water samples using shotgun metagenomics to detect plant viruses. Results revealed a high plant virus abundance in wastewater, with tomato brown rugose fruit virus (ToBRFV) consistently co-occurring with pepper mild mottle virus (PMMoV), cucumber green mottle mosaic virus (CGMoMV), melon necrotic spot virus (MNSV) and tomato mosaic virus (ToMV). These viruses primarily belong to the Tobamovirus genus (Virgaviridae), except MNSV (Carmovirus, Tombusviridae). Near-complete ToBRFV genomes were assembled from thirteen samples with adequate sequencing depth and coverage.

Then, we implemented a targeted multiplex RT-ddPCR approach to specifically detect PMMoV, ToBRFV, CGMoMV, and MNSV. Using this more sensitive and specific method, the results from year-long sampling confirmed their widespread presence, detecting up to 109 genome copies/100 mL. Temporal analysis revealed seasonal fluctuations for CGMoMV and MNSV RNA, contrasting with stable ToBRFV and PMMoV RNA levels throughout the year.

This study provides the first comprehensive evidence of the occurrence of genome of diverse RNA plant viruses in Luxembourg's wastewater, including the economically devastating ToBRFV. Current research is evaluating the presence of these viruses in reclaimed water after treatment, which is crucial for developing safe reuse protocols. Future work will establish the virus infectivity in environmental waters and conduct comprehensive risk assessments for agricultural irrigation applications.

Our preliminary findings emphasise the need for plant pathogen monitoring in water reclamation strategies, highlighting an underexplored dimension of wastewater reuse safety for food security.

Acknowledgement:

This study was supported by the Luxembourg National Research Fund (C21/BM/15793340/VIRALERT), and jointly by the Fond de la Gestion de l’Eau and the Health Directorate in the framework of the SUPERVIR Project.

Zahra Hejazi¹*, Torsten Bohn¹

¹Nutrition and Health Research Group, Department of Precision Health, Luxembourg Institute of Health

*Presenting author

Polychlorinated biphenyls (PCBs), classified as persistent organic pollutants (POPs), are known for their lipophilicity and bioaccumulation in the food chain, leading to human exposure through diet. The European Food Safety Authority (EFSA) analyzed over 30,000 food and feed samples from 26 countries to evaluate PCB levels. Out of these, 10% and 3% of the samples contained above maximum levels of dioxin and dioxin-like PCBs and of non dioxin-like PCBs, respectively. In general, fish, meat, and dairy products had the highest contribution to dietary exposure to PCBs. One consequence of this exposure could be an increased risk for cardiometabolic diseases, such as type 2 diabetes (T2D), through oxidative stress, inflammation, and modulation of several transcription factors such as Nf-kB and nuclear receptors, for example RXR/PPARs that could act on the immune, and hormonal systems. Considering the importance of the topic, an ongoing PhD project at Luxembourg Institute of Health is focusing on the relationship between POPs and T2D, aiming to explore multiple exposure dimensions. Specifically, this project strives to unravel the potential mitigating role of healthy, balanced, and rich in micronutrient diet on this relationship. This is achieved by combining data from EFSA and food consumption patterns across European countries from the EPIC (European Prospective Investigation into Cancer and Nutrition) project. The project also emphasizes the need for effective strategies to monitor, regulate, and reduce PCB exposure to protect public health. Therefore, here we aimed to highlight the extent of PCB contamination in Europe and underscore the associated health risks.

Chantal J. Snoeck¹*, Aurélie Sausy¹, Lena de Baets², Louis Kox³, Jill Gaasch³, Guillaume Fournier², Marianne Jacobs⁴, Manon Bourg², Caroline Merten², Judith M. Hübschen¹

¹Clinical and Applied Virology Group, Department of Infection and Immunity, Luxembourg Institute of Health

²Luxembourg Veterinary and Food Administration (ALVA)

³Centre de Soins pour la Faune Sauvage, Natur&Emwelt

⁴Administration de la Nature et des Forêts (ANF)

*Presenting author

Highly pathogenic avian influenza (HPAI) viruses have been repeatedly detected in wild birds in Europe for the past decade and are regularly transmitted to poultry upon direct or indirect contact. In Luxembourg, several occurrences of HPAI in domestic and wild birds have been detected over the past 2 decades of surveillance. Recently, the number of HPAI events in wild mammals has drastically increased in Europe and the Americas, especially in carnivores preying on sick or dead birds, mammals kept for fur production and sea mammals. Besides animal health and wildlife conservation issues, increased circulation of HPAI strains in mammals provides more opportunities for HPAI viruses to acquire specific mutations for adaptation, increasing the pandemic risk. Surveillance is thus crucial to identify and monitor emerging threats. In parallel with surveillance in birds, screening of wild carnivores was thus initiated in 2022 in Luxembourg, with more than 300 animals from all over the country tested since then. Red foxes, well represented in HPAI positive cases in Europe likely due to their preying behavior, constitute the main species tested in Luxembourg, followed by invasive raccoons. No HPAI virus has been detected so far in wild mammals in the country, despite occasional HPAI cases in wild and domestic birds during the 2021-2022 and 2022-2023 seasons. However, the situation is highly dynamic and requires continuous monitoring for both animal and public health.

Acknowledgements

We wish to thank all the people involved in animal care, sample collection and testing. HPAI surveillance activities in wild carnivores are a collaborative effort between LIH, ALVA, Administration de la Nature et des Forêts and the Centre de Soins pour la Faune Sauvage. These activities are supported by co-funding from the European Union’s EU4Health programme under Grant Agreement No. 101132473 OH4Surveillance, the Ministry of Agriculture, Food and Viticulture of Luxembourg and LIH.

Disclaimer: Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or HaDEA. Neither the European Union nor the granting authority can be held responsible for them.

Michael Eickermann¹*, Matteo Ripamonti¹, Marine Pallez-Barthel¹, Alexander Weigand², Carmelo Rapisarda³, Imen Kharrat-Jarboui³, Wolfgang Jarausch⁴, Hannes Schuler⁵

¹Luxembourg Institute of Science and Technology

²Musée national d'histoire naturelle Luxembourg

³Fondation Faune-Flore

⁴RLP AgroScience

⁵Free University of Bozen-Bolzano

*Presenting author

The apple tree’s ecological community also encompasses pest insects, including so-called psyllids, which represent a particularly intriguing insect group. Since 2018 the occurrence of over 60 psyllid species in Luxembourg is documented. In total, three psyllid species are found on apple trees in our region, which play a significant role in the transmission of plant pathogens known as phytoplasmas. These are bacterial-like agents that cause the so-called “apple proliferation” disease in apple trees. An infection leads to the sprouting of axillary buds, which produce slightly twisted shoots with a broom-like appearance. Fruits from affected trees remain small and are unsuitable for storage. In South Tyrol, particularly this psyllid-transmitted disease results in substantial economic losses. Currently, two research projects (VectoRise and PsyPhyPaths2) are underway in Luxembourg investigating the distribution of vector insects and the pathogens they transmit in the Greater Region. In addition to extensive insect monitoring, molecular genetic analyses will identify the specific pathogen strains and thus characterize the existing pathosystem in detail. Both projects have a significant impact on food security regarding apple production.

Funding: VectoRise is funded by the Fonds National de la Recherche. And the project PsyPhyPaths2 is funded by the Ministry of the Environment, Climate and Biodiversity of Luxembourg.

Sabina Burla, Giovanna Radicchio, Arno C. Gutleb*

INVITROLIZE, Luxembourg

*Presenting author

Allergic diseases represent a growing global health burden, with food and respiratory allergies contributing substantially to morbidity. Inhalation of sensitizers from food sources may prime the immune system for exacerbated responses upon ingestion, underscoring the urgent need for reliable allergenicity assessment of novel food proteins and additives. Current new approach methodologies (NAMs) for skin sensitization fail to discriminate respiratory sensitizers, highlighting the necessity of physiologically relevant models for the respiratory tract.

ALIsens® is available in various sizes from 6- to 24-well inserts to enable high-throughput screening (HTS). The model incorporates human alveolar type II epithelial (A549), endothelial (EA.hy926), and monocyte (THP-1) cell lines, fostering a tissue-like microenvironment through direct cell-cell interactions and paracrine signaling. Structural resemblance to the alveolar region was confirmed microscopically, and exposures were performed at the air-liquid interface (ALI) using a panel of known respiratory sensitizers and non-sensitizers.

Cell viability was assessed by resazurin assay 24 h post-exposure, and dose–response curves were generated for apical, basolateral, and integrated compartments. Flow cytometry of CD54, CD86, and TSLPr was conducted at non-cytotoxic concentrations (≥75% viability). The system successfully distinguished respiratory sensitizers from non-sensitizers and correctly identified pro-haptens frequently misclassified by other NAMs.

These findings demonstrate that ALIsens®, the 3D model for the alveolar barrier provides a physiologically relevant and scalable in vitro platform for predicting respiratory sensitization. The approach holds promise for efficient hazard assessment of food components and chemicals, addressing a critical gap in current regulatory testing strategies.

Cuenca-Ortolá M¹, Gandía M¹, Filice S²*, Gamero A¹, Cilla A¹

¹Bionutest group, Department of Preventive Medicine and Public Health, Food Sciences, Toxicology and Forensic Medicine, University of Valencia, Spain

²Microtarians SIS, Social Impact Company, Luxembourg

*Presenting author

The Microtarians SIS initiative promotes a low-tech, community-driven approach to food fermentation. It supports circular food systems by upcycling local, often wasted resources into high-value functional products and improving the nutritional profiles of Traditional Mediterranean Recipes (TMR).

Within the framework of the MEDIET4ALL project and in collaboration with the University of Valencia, this study investigates the potential of fermentation to enhance the antioxidant properties of traditional plant-based ingredients (black garlic, lemon, and kombucha), aiming for their functional integration into TMR.

Through comparative analyses of Total Antioxidant Capacity (TAC) and total polyphenols (TP) between homemade (HM) and industrial (IN) fermentation processes, our results consistently show superior antioxidant profiles in HM products.

Notably, ORAC values for black garlic reached 182,587 µM Trolox/100g DW in HM samples versus <100,000 µM in IN counterparts (+80% increase). Fermented lemon exhibited 363,294 µM Trolox/100g DW, reflecting a +275% increase relative to fresh and industrial references. Kombucha samples displayed 4717 mg GAE/100g DW total polyphenols, approximately 10-fold higher than typical industrial samples (400-500 mg GAE/100g DW).

These enhancements are attributed to the preservation of microbial diversity, absence of pasteurization, and reduced processing steps inherent to HM fermentation, which foster bioactive compound release.

In conclusion, fermentation is a key determinant in optimizing antioxidant properties of functional foods. We advocate for the co-creation of a doctoral research program combining nutritional biochemistry and circular economy to validate and scale up the Microtarians SIS initiative.

Patrick Reteng¹*, Cédric Simon², Carlos Gamio¹, Aurélie Sausy¹, Aleksandra Krawczyk¹, Alexander M. Weigand², Judith M. Hübschen¹

¹Clinical and Applied Virology Group, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg

²Musée National d’Histoire Naturelle de Luxembourg, Luxembourg, Luxembourg

*Presenting author

Historically absent in Luxembourg, the tick Dermacentor reticulatus (Fabricius, 1794) is now established in the country. This tick species is known as the vector of several pathogens, but so far, data about pathogen prevalence in the local D. reticulatus population were missing. To address this gap, 510 adult D. reticulatus ticks were collected from May to June 2024 in the South of Luxembourg. The ticks were identified morphologically and nucleic acids extracted from the ticks were screened with multiplex qPCRs for various tick-borne pathogens. Rickettsia sp. was the predominant pathogen found (58/510; 11.4%) and further analysis of partial ompB and gltA sequences revealed that the strains formed a cluster together with R. raoultii, which is capable of infecting humans and animals. The sequences obtained from ticks in Luxembourg are highly similar, suggesting limited genetic diversity of R. raoultii in the country. Interestingly, the prevalence of Rickettsia infection differed between collection sites, which could be attributed to environmental differences between locations. Higher infection prevalence was associated with presence of agricultural land connected to natural vegetation, while land heavily used for agriculture was associated with decreased prevalence. However, the discrepancy in prevalence might also be a result of the “founder effect,” considering that R. raoultii is horizontally transmitted in the ticks. As the population of D. reticulatus is expected to further expand due to warming climate and movements of humans and animals, ongoing surveillance of tick distribution and associated pathogens is necessary to identify and monitor risk areas.